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Car Rottiserie - Welding Advice Plz

11-17-2006, 07:19 PM

Been welding for about 10yrs, currently using Miller 175, though haven't tackled anything of this magnitude. Most of the steel tube is 3/16 wall and I'm fairly comfortable with the MM175 at this thickness. Plan to use .035 wire and 75/25 mix.

There are some 1/2in gussets, however, so I'm thinking those will definitely need multiple passes. Also will probably do multiple passes on all the high stress joints regardless of thickness. Can someone pls describe the procedure for multiple pass welding, for example, welding 1/2 plate to 3/16 wall tube.

i've been welding for just over 4 years and i'm a third year fresh outta school. if you plan on welding a 1/2 inch gusset to 3/16 tubing there isn't any need for multi pass welds. you're fillet weld only has to be as big as your thinnest metal (3/16). if you were to multi pass and make a 3 pass 3/8 fillet you'd actually weaken the gusset. this would be because of the heat stress put into the thin material. so all said and done a 3/16 fillet is all you need, just make sure to wrap the corners on your gusset. instad of stopping when you get to the corner of the gusset continue your bead around onto the other side.

Comment

I am not sure which area exactly you are talking about. It would be helpful to know what type of process you are planning on using (mig-tig-stick?). Does this assembly have to be togeather to weld it or can sections be welded then assembled ? If you can weld the rotating piece seperate from the frame it would make it easier to get at some of the areas,allowing you to do most of the welds in a flat position on a welding table. Ya always lay better beads if you are comfortable, at least I do.

Comment

Sorry for confusion. I've circled the 2 critical areas. Area on right is the one I addressed above, that is, intersection of inner rotator tube with vertical sleeve. You can also see a couple small adjacent gussets. The area on left is the outer rotator tube intersection with (and mounted to) the vertical post. These are both critical stress areas.

The inner pin and attached assembly can be separated from the outer tube assembly.

Comment

set up just like danno said earlier. Your machine is capable for sure. The gussets are where a good percentage of the strength is, as long as they are placed in the right area to work against the direction of load you should be able to hold something pretty heavy off that puppy with no problems. If thats a engine stand ( thats a guess?) I would suspect you wont have any issues hanging a big block off of it. Dont over look the leverage working against the base of your project, there may be more torque trying to break the upright off the base then up on top. I know if you pitch the upright back to put more load "over center" it will greatly reduce the stress working against the base of the upright. hope that makes sense-been up all night on a job and just killing time here and there on the computer.

Comment

It is designed around a beefed up engine stand configuration. Below is entire rotisserie. As to the base reinforcement...thats 1/2 plate gusset and 2 x 2 x 1/4 side supports. If you look carefully you can see gussets on the vertical member of the arm assembly.

Comment

Those look stout to me. I guess I didnt exactly know what you where making, now I get it. I think you got them engineered to be plenty strong, the bottom gussets and supports look plenty sufficient. Looks well thought out.